On Shorpy:Today’s Top 5

The building to the right ("Keith's High Class Vaudeville") is where "the new" Old Ebbitt Grill is today. Now called Metropolitan Square, the building is a just a facade fronting a large enclosed atrium that is part of a modern office building.

I would assume the individual letters of the names on the marquee above the awning would be lit with bulbs... but I can't figure out how they were wired? I can see "blanks" for example on either side of "HYAMS", so would those be removed before accepting a new letter-square? Or perhaps the letters were magnetic, and just "stuck" to the frame? I never thought about it until I saw this picture... and still can't figure out how each bulb would get electricity. Oh well. It's showbiz!